As it is necessary to compress the large aerial image data from the large-array aerial CCD camera, an image compression algorithm named as Rate Pre-allocated Compression Algorithm (RPCA) based on bit plane coding is proposed by studying variety of image compression algorithms. First, the relative redundancy between pixels of the image should be refused by using multi-level wavelet transform to original image. Second, according to the theory of rate distortion and principle which is the more important to image reconstruction in various sub-bands, the number of bit-rate for different sub-bands should be allocated in the process of actual coding that has been computed. Finally, the coefficients bits are coded by adaptive MQ arithmetic coder. So the careful embedded code stream is produced. Experiment results shows that this algorithm rate allocation is accurate, and the quality of image compression is comparable to the JPEG2000 standard, supporting any lossless to loss image compression ratio, but the complexity is far lower than the JPEG2000 standard and suitable for hardware implementation.