选项1

使用raw字符串，r''

>>> "{\"key1\":\"value1\",\"key2\":\"value2\"}"
'{"key1":"value1","key2":"value2"}'
>>> r"{\"key1\":\"value1\",\"key2\":\"value2\"}"
'{\\"key1\\":\\"value1\\",\\"key2\\":\\"value2\\"}'

选项二

使用json.dumps()

>>> from json import dumps
>>> s = "{\"key1\":\"value1\",\"key2\":\"value2\"}"
>>> s
'{"key1":"value1","key2":"value2"}'
>>> dumps(s)
'"{\\"key1\\":\\"value1\\",\\"key2\\":\\"value2\\"}"'
>>> dumps(s)[1:-1]
'{\\"key1\\":\\"value1\\",\\"key2\\":\\"value2\\"}'

总结

下面是两种方法的示例：

import json

a = "{\"key1\":\"value1\",\"key2\":\"value2\"}"
a_raw = r"{\"key1\":\"value1\",\"key2\":\"value2\"}"

print(a)

print(a_raw)
print(json.dumps(a)[1:-1])

# they are the same
assert a_raw == json.dumps(a)[1:-1]