Portable biochemical analyzers are mainly used in the patients' self-monitoring and the medical institutions' rapid primary diagnosis. With the increased population of diseasedness and the enhancing health consciousness of people, they have found an ever-widening range of application. However, most of the present portable analyzers, no matter inland or outland, can only serve in the single-parameter detecting, and the accuracy of their test results, generally speaking, are not satisfied. In order to change this kind of status, the work described in this paper is focused on the development of a portable biochemical analyzer which is capable of testing 4 parameters including,blood sugar, cholesterol, uric acid and acetone body. Adopting the enzyme immobilizing technology and the electrochemical detecting method, the complete and practicable system design was proposed and the prototype was constructed as well. The comparing detecting experiments of partial parameters between our instrument and the large biochemical equipment indicate that out instrument operates steadily and its results correlate well.