The Ki-15-I was almost immediately placed into operational service at the beginning of the war with China in 1937. The aircraft proved useful in the early period of the Second Sino-Japanese War and performed missions deep into Chinese strategic rear areas, as far as reaching Lanzhou, and in particular serving as pre-strike guide and post-strike observation during the years-long Battle of Chongqing-Chengdu. Its high speed gave it a distinct advantage until the Chinese Air Force acquired Soviet-made Polikarpov I-16 Type 17 fighters; a Ki-15 was shot down along with three bombers by I-16 Type 17 fighters of the 24th PS, 4th PG over Liangshan Airbase on 20 May 1940. It was used for level bombing, close support and photo reconnaissance before being eventually replaced by the Mitsubishi Ki-30.