你必须使你的json对象变平

DataTable dt = JsonConvert.DeserializeObject<DataTable>(prettyJson, new ToDataTableConverter());

public class ToDataTableConverter : JsonConverter<DataTable>
{
    public override DataTable ReadJson(JsonReader reader, Type objectType, DataTable existingValue, bool hasExistingValue, JsonSerializer serializer)
    {
        var rows = new JArray(JObject.Load(reader).Properties()
                       .SelectMany(x => GetRows(x.Values())));

        return rows.ToObject<DataTable>();
    }

    private JArray GetRows(IEnumerable<JToken> val)
    {
        var list = new List<JObject>();
        foreach (JProperty jo in val)
        {
            var key = jo.Name;
            foreach (JObject o in jo.Value)
            {
                o.AddFirst(new JProperty("key", key));
                list.Add(o);
            }
        }
        return new JArray(list);
    }

    public override void WriteJson(JsonWriter writer, DataTable value, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }
    public override bool CanWrite
    {
        get { return false; }
    }
}

输出

[{"key":"390","root":"AAPL","expiry":"2024-06-21T00:00:00"}]