Water pollution control is one of the most important compulsory and crucial courses for undergraduates majoring in environmental engineering. In view of the analysis of the current situation of the bilingual teaching for specialized courses in engineering field, course reform of auxiliary bilingual teaching is discussed in the paper. Under the condition of original teaching hours plan, the model of auxiliary bilingual teaching is carried out by reasonable adjustments of class organization mode, optimization of multimedia courseware, diversity of exercise after class etc. Auxiliary bilingual teaching of the course can enhance the understanding of specialized contents, increase reading & analysis ability and written skills ability for undergraduates significantly under the premise of teaching objectives. It has a certain valuable feasibility of implementation.