Despite the evidence, he continued to plead not guilty during the trial.

plead 是动词，意思是"恳求、申辩、辩护"。在法律语境中，plead 特指"在法庭上正式陈述（认罪或不认罪）"，plead not guilty 就是"申辩无罪"或"不认罪"的意思。