According to traditional flatness detection for elevator landing door was time consuming, low precision and so on, an automatic noncontact detection device for elevator landing door was put forward. The whole scheme design, the structural design and control system about this flatness non-contact detection device were illustrated.The measurement and control system was developed based on industrial computer and LabVIEW.The flatness detection device was verified by laser tracker,meeting the requirements of design accuracy.This device is easy to operate, effectively shortens the measurement time, raises the detection accuracy, reduces people’s labor intensity. Now this flatness non-contact detection device for elevator landing door has been successfully applied stably and reliably.