The invention discloses a detection apparatus and detection method for drug effect of an anti-cancer drug, i.e., hydroxycamptothecine. The detection apparatus comprises an electrochemical work station, a flow cell, a substrate arranged in the flow cell, an electrode chip arranged on the substrate, solution boxes, micro pumps, a computer, etc. According to the invention, the peak value of the signal-to-noise ratio of hydroxycamptothecine with unknown drug effect is compared with the peak value of the signal-to-noise ratio of a frequently used cancer treatment drug, i.e., cisplatin, and the drug effect and dosage of hydroxycamptothecine are obtained in comparison with the known drug effect and dosage of cisplatin. The detection apparatus and detection method provided by the invention have the characteristics of high detection efficiency, good accuracy and capacity of providing reliable bases for safe usage of hydroxycamptothecine so as to ensure safety of patients.