When Duan Qirui refused to validate the Constitution Cheng and fellow Admiral Lin Baoyi sailed their fleets down south to join with the 'Constitutional government' of Sun Yat-sen. He was assassinated in Haizhu District, Guangzhou, in 1918.
Duan Qirui's refusal to ratify the Constitution led Cheng and Admiral Lin Baoyi to sail their fleets to Guangzhou, where they allied with Sun Yat-sen's 'Provisional government', resulting in Duan's assassination in Haizhu District in 1918.