Depends what you mean by "Chinese Police". If you mean police under the control of local Chinese governments then that could be some ask .
If you are looking at Chinese in foreign service in the 1920s /'30s then the modern Hong Kong Police look may not be the best start point. The uniform is essentially 1960s and very British in origin.
If you want police for the International Concessions then the HK Police look won't fit the bill ('scuse the pun).
Probably the most famous police presence in places like Shanghai were the Sikh contingent.
A little bit earlier (1910) but here's a pic of some Sikh policemen, presumably kitted out for a review.
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The various International concessions would have police whose uniform, not surprisngly mirrors to greater or lesser degree that of the nation in question. For some nice pics of French police in Shanhai try this site:
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This webpage has a nice potted history aimed at the gamer for the Shanghai Municipal Police.
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