我认为最简单的解决方案是使用光标关联到您的编辑器，以便做格式化。这样您就可以设置前景，背景，字体样式……下面的示例用不同的背景标记匹配项。

from PyQt4 import QtGui
from PyQt4 import QtCore

class MyHighlighter(QtGui.QTextEdit):
    def __init__(self, parent=None):
        super(MyHighlighter, self).__init__(parent)
        # Setup the text editor
        text = """In this text I want to highlight this word and only this word.\n""" +\
        """Any other word shouldn't be highlighted"""
        self.setText(text)
        cursor = self.textCursor()
        # Setup the desired format for matches
        format = QtGui.QTextCharFormat()
        format.setBackground(QtGui.QBrush(QtGui.QColor("red")))
        # Setup the regex engine
        pattern = "word"
        regex = QtCore.QRegExp(pattern)
        # Process the displayed document
        pos = 0
        index = regex.indexIn(self.toPlainText(), pos)
        while (index != -1):
            # Select the matched text and apply the desired format
            cursor.setPosition(index)
            cursor.movePosition(QtGui.QTextCursor.EndOfWord, 1)
            cursor.mergeCharFormat(format)
            # Move to the next match
            pos = index + regex.matchedLength()
            index = regex.indexIn(self.toPlainText(), pos)

if __name__ == "__main__":
    import sys
    a = QtGui.QApplication(sys.argv)
    t = MyHighlighter()
    t.show()
    sys.exit(a.exec_())

代码是不言自明的，但如果你有任何问题，只是问他们。

以下是如何在QTextEdit中突出显示文本的示例：

#!/usr/bin/env python
#-*- coding:utf-8 -*-

from PyQt4.QtGui import *
from PyQt4.QtCore import *

class highlightSyntax(QSyntaxHighlighter):
    def __init__(self, listKeywords, parent=None):
        super(highlightSyntax, self).__init__(parent)
        brush   = QBrush(Qt.darkBlue, Qt.SolidPattern)
        keyword = QTextCharFormat()
        keyword.setForeground(brush)
        keyword.setFontWeight(QFont.Bold)

        self.highlightingRules = [  highlightRule(QRegExp("\\b" + key + "\\b"), keyword)
                                    for key in listKeywords
                                    ]

    def highlightBlock(self, text):
        for rule in self.highlightingRules:
            expression = QRegExp(rule.pattern)
            index      = expression.indexIn(text)

            while index >= 0:
              length = expression.matchedLength()
              self.setFormat(index, length, rule.format)
              index = text.indexOf(expression, index + length)

        self.setCurrentBlockState(0)  

class highlightRule(object):
    def __init__(self, pattern, format):
        self.pattern = pattern
        self.format  = format

class highlightTextEdit(QTextEdit):
    def __init__(self, fileInput, listKeywords, parent=None):
        super(highlightTextEdit, self).__init__(parent)
        highlightSyntax(QStringList(listKeywords), self)

        with open(fileInput, "r") as fInput:
            self.setPlainText(fInput.read())        

if __name__ == "__main__":
    import  sys

    app = QApplication(sys.argv)
    main = highlightTextEdit("/path/to/file", ["foo", "bar", "baz"])
    main.show()
    sys.exit(app.exec_())

QT5更新了RegEx，参见QRegularExpressionhttps://dangelog.wordpress.com/2012/04/07/qregularexpression/

我更新了第一个使用游标的示例。
请注意以下更改：
1.这并不包含编辑，而是使用内部的编辑框，它可以很容易地更改为允许您传入编辑小部件。
1.这是一个正确的正则表达式查找，而不仅仅是一个单词。

def do_find_highlight(self, pattern):
        cursor = self.editor.textCursor()
        # Setup the desired format for matches
        format = QTextCharFormat()
        format.setBackground(QBrush(QColor("red")))
        
        # Setup the regex engine
        re = QRegularExpression(pattern)
        i = re.globalMatch(self.editor.toPlainText()) # QRegularExpressionMatchIterator

        # iterate through all the matches and highlight
        while i.hasNext():
            match = i.next() #QRegularExpressionMatch

            # Select the matched text and apply the desired format
            cursor.setPosition(match.capturedStart(), QTextCursor.MoveAnchor)
            cursor.setPosition(match.capturedEnd(), QTextCursor.KeepAnchor)
            cursor.mergeCharFormat(format)