A kinematic supporting project had been designed in order to resolve installation and high precision positioning for spatial optical remote sensor. First, constraint-screw theory was introduced, including the concept of screw, modified K-G equation and physical meaning of communal constraint and redundant constraint. Second, a mode of 3-RRR spatial parallel mechanism was proposed as kinematic support scheme. Constraint-screw algorithm was applied to analyze the problem how per embranchment circumscribed working platform′s degree of freedom at ideal state, and all embranchments acted on the working platform together that gave birth to communal constraint and redundant constraint. After that, the clearances of kinematic pairs in unit of micrometer were inducted to investigate the assignment of degree of freedom at actual circumstance, the quantity of over-constraint at idea state was compared with the situation at actual state including clearances. Finally, Euler equation was adopted to optimize components′ configuration while the design of supporting project was completed. Experimental results indicate that the value of remote sensor′s displacement along every axis is in unit of 0.01 mm, and its rotation angle around x, y, z axis is 3.95″, 1.86″, 1.81″. This supporting project satisfies the request for support and high precision positioning for spatial optical remote sensor.