Energy in wireless sensor networks is one of the most important resources, most of the energy is consumed in communication. The wireless transmission of a single bit requires over thousand times energy more than a single 32-bit computation, so data compression provides a viable approach towards the preserved energy by reducing packet size. In this article, a new simple and effective lossless data compression which suited to latency tolerant transmission in environmental monitoring WSNs is proposed. The algorithm realizes data transformation and rearrange of bits at first, then RLE is used to compress the rearranged bit stream, finally Huffman coding is used to record the run-length. At last, the proposed algorithm is evaluated and compared with other algorithms. The results show that it is remarkable in reducing storage space and increasing the compression ratio.