我觉得有错：
1.如果是句子应有主语,但此句没有；若是省略句应该有一定语言环境.如果是短语则应写成”Hearing 或to hear"
2.我们是听声音而不是听笛子,所以是"the sound of the flute"
可以改为：Hearing the sound of the flute in the spring morning of beijing.
或：I heard the sound of flute in the spring morning of Beijing .