In the laser device experiment,the time integral of X ray image emitted from black cavity target can be obtained by the principle of keyhole imaging.A new imaging device with triple magnification is proposed for the first laser plasma interaction experiments,where X ray time integral images in the low and high energy segments are obtained by installing the imaging device with multi layer mirror at an angle of 30° to the target axis to observe the re radiation of the cavity wall.The development of a keyhole camera for the first laser plasma interaction experiments is carried out,including optical design and structural design.The system performance is tested off line and experimented online.The imaging optical path and the energy selection effect of two kinds of mirrors are simulated,and the effect of multi layer mirror,filter and spectrum distribution contribution on the imaging results is obtained through the simulation of the optical path simulation.FLASH is used to simulate the experimental radiation field distribution as an input to the imaging simulation.Finally,the imaging results obtained by the device are compared with the results obtained from the simulation calculations.The experimental results are basically consistent with the simulation results,obtaining the distribution of the X ray signal,the ideal experimental data,and deepening the understanding of the internal physical phenomena.Therefore,the simulation capability of pinhole imaging is established,which can predict the imaging results and guide the design of pinhole cameras.