The utility model provides a simple and easy biological assay auxiliary device that shoots, comprises a box bod, the box body is the cuboid form, the box body bottom is the opening completely, box body top central point puts to set up and shoots the hole, it is circularly to shoot the hole, box body side bottom horizontal array sets up multiunit daylighting hole, the daylighting hole is circularly, daylighting hole both ends set up the track, track and box body fixed connection, the light screen is through vertical plate body that sets up and track sliding connection on the daylighting hole, the light screen is the L type, transversely set up the lever on the light screen, the plate body is the rectangle, the length and the wide diameter that all is greater than the daylighting hole of plate body, the device is through the shooting hole at box body top and settings that suit of box body bottom daylighting hole and light screen, the photo of shooting, and regular, the big or small unanimity that forms images, the color is even, does not reflect light, is showing to have improved biological assay photo quality, through the effective fixing box body of fixed block for shooting process is more stable, has extensive practicality in experiment formation of image field.