Chang was born on October 10, 1908, in the village of Dunhòu (敦厚), which lies 64 miles (103 km) northwest of Taiyuan, the capital city of Shanxi province, in Qing dynasty China. His family was able to provide for him a good education, and in 1933, he obtained a bachelor's degree in animal psychology from Tsinghua University in Beijing. In 1938, Chang won a national competition and was awarded one of the few available fellowships to study abroad. He went to spend a year at the University of Edinburgh studying agricultural science, but found that the University was not to his liking due to a combination of the cold weather and a perceived bias against foreigners there. On an invitation from Arthur Walton, Chang left the University of Edinburgh and went on to research ram spermatoza at Fitzwilliam College, Cambridge. With his newfound interest in reproductive biology, Chang immersed himself in research, working together with other scientists such as John Hammond and F.H.A. Marshall, under the tutelage of Arthur Walton. In 1941, he was awarded a PhD in animal breeding by the University of Cambridge on his observations on the effect of testicular cooling and various hormonal treatments on the respiration, metabolism, and survival of sperm in animals.