The invention discloses a planer array projection device and a depth camera. The planer array projection device comprises a planer array light source and a diffractive optical element, wherein the planer array light source comprises multiple light emitting elements for emitting laser; the diffractive optical element is used for carrying out beam expanding on the laser emitted by the planer array light source and converting the laser to patterned laser; the multiple light emitting elements are arranged into a first optical pattern; a pattern formed after a single beam of light is expanded through the diffractive optical element is a second optical pattern; the first optical pattern and the second optical pattern are composite to form a composite optical pattern, and the composite optical pattern is the patterned laser pattern; the first optical pattern, the second optical pattern and the composite optical pattern comprise multiple light beams; and the light beam layout in the composite optical pattern has local irrelevance, and the uniformity index is smaller than a preset threshold. Through the above mode, better optical projection effects can be achieved with a smaller light source, integration in a small device is realized, and the light weight and the thinness of the device are improved.