There is provided a biochemical analyzer and a method of cleaning fluid components of the same. The biochemical analyzer includes a reagent adding mechanism, a sample adding mechanism, at least one reaction cup, a cleaning mechanism and a waste pipeline connected to the cleaning mechanism. A control system is employed, wherein the control system has a cleaning mode for cleaning fluid components of the biochemical analyzer, having: a) a water injection step; and b) a water discharge. With the cleaning method, the fluid components such as the water drawing device and waste valve on the waste pipeline may be automatically cleaned without manual intervention.