The utility model provides a multifunctional testing device, during it will put same reactor into by detection electrode with as the standard electrode that the reference was compared to the parallel, reactor's contrast test condition is set for according to predetermined detection project and after, observe and the record by detection electrode and standard electrode's data, then according to data judgment by detection electrode's performance, by detection electrode at least including miniature pH electrode and miniature oxide electrode, non -contact pH detecting system and the non -contact dissolved oxygen detection device of dissolving. The detection project includes at least: the miniature pH electrode performance of different temperatures, different pH value conditions detects, the miniature DO electrode performance of different temperatures, different dissolved oxygen concentration conditions detects, the miniature DO electrode performance of different temperatures, different pH value conditions detects, the miniature pH electrode performance of different temperatures, different dissolved oxygen concentration conditions detects, under the condition of different reactor pressure, the performance that above -mentioned each state was respectively surveyed the electrode down detects.