如果您使用Newtonsoft Json.NET库，则可以执行以下操作。

定义一个转换器，以所需的方式写入键/值对的列表：

class MyConverter : JsonConverter
{
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        List<KeyValuePair<string, object>> list = value as List<KeyValuePair<string, object>>;
        writer.WriteStartArray();
        foreach (var item in list)
        {
            writer.WriteStartObject();
            writer.WritePropertyName(item.Key);
            writer.WriteValue(item.Value);
            writer.WriteEndObject();
        }
        writer.WriteEndArray();
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        // TODO...
    }

    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(List<KeyValuePair<string, object>>);
    }
}

然后使用转换器：

var keyValuePairs = new List<KeyValuePair<string, object>>
                    {
                        new KeyValuePair<string, object>("one", 1),
                        new KeyValuePair<string, object>("two", 2),
                        new KeyValuePair<string, object>("three", 3)
                    };

JsonSerializerSettings settings = new JsonSerializerSettings { Converters = new [] {new MyConverter()} };
string json = JsonConvert.SerializeObject(keyValuePairs, settings);

这产生 [{"one":1},{"two":2},{"three":3}]