From Singapore, Xu visited major Southeastern Asian cities where Chinese immigrants lived, and he continued to contribute to the resistance and relief work in China with his art. During that time, Xu also visited India upon Nobel laureate Rabindranath Tagore's invitation and stayed there for months, exchanging cultural ideas.

Singapore witnessed one of Xu's most productive periods, during which he achieved maturity in integrating the realistic method of Western painting into the poetic atmosphere and philosophic take of classic Chinese painting.

Before his departure for China, Xu received a calligraphy piece from the Chinese community in the Malaysian state of Perak that read, renfeng yuanbo ("man of benevolence spreads his high ideas far away"), hailing his patriotism and efforts to spread Chinese culture overseas.

Renfeng Yuanbo is the name of an ongoing exhibition at Peon Art Museum Chongqing that shows 23 paintings and drawings by Xu from his time in Singapore.