The invention relates to a special vehicle-mounted double-grid-format system for automatically adjusting and weakening the absorption intensity of a signal panel cover and a method for adjusting and weakening the signal intensity, in particular to an accessory of public safety monitoring and management equipment installed on a mobile vehicle and used for obtaining a mobile phone number and a system setting method. The device is invented for public security personnel to accurately master the mobile phone number carried by a specific person, and equipment for detecting the mobile phone number isa single pile identification device. The performance of the single pile identification device is improved. The spatial special-shaped weakening signal plate cover is characterized in that the spatialspecial-shaped weakening signal plate cover is in a spatial special shape and comprises two reflecting plates or absorbing plates with grid gaps; And the width of the grid gap is adjusted by adjusting the dislocation proportion value of the two wrenches, so that the reduction intensity of the received mobile phone signal is adjusted.