Abstract: The robot microarrayer system for microplate is designed and developed.A 3-DOF sliding cantilever orthogonal structure is adopted in the manipulator,and the manipulator stiffness is calculated with finite element method.Meanwhile, the design proposal of print-head cleaning and drying,air purification and humidity control is given,and hardware structure and software function tree of the control system are set up.The experiment result shows that the model machine is highly automated and stable,the repeated positioning performances of manipulator,±3.6μm in X axes and±2.8μm in Y axes,can meet application requirements of microarray in biology.