Since the turn of the century, China has shown its determination to change its examination-oriented tradition. It started assessment reforms and raised a series of expectations regarding teacher assessment literacy. At the same time, China experienced rapid internal migration, with urban public schools accepting huge numbers of migrant students in recent years. This study explored urban public-school teachers' assessment literacy in China's Zhengzhou city. The teaching of nine teachers from nine urban public schools were observed and follow-up interviews conducted between 2018 and 2019. The study provides insights into the contextual challenges that face teachers with regard to assessment in urban public schools in China.