The utility model relates to a car door inner panel which solves the problems of complicated structure, more parts and high cost found in the car door inner panel in the prior art. The car door inner panel comprises an inner panel front part and an inner panel rear part; the thickness of the inner panel front part is 1.4 mm; the thickness of the inner panel rear part is 0.8 mm; the inner panel front part is welded with the inner panel rear part through laser butt-welding; the car door inner panel saves source material, reduces punching process and the number of parts of vehicle body, reduces the production cost and improves the collision performance through structural improvements so that the whole car is ensured to have better safety performance.