We propose an adaptive cooperative forward error correction (ACFEC) based on energy efficiency combining Reed-Solomon (RS) coder algorithm and multiple input multiple output (MIMO) channel technology with monitoring signal-to-noise ratio (SNR) in wireless sensor networks. First, we propose a new Markov chain model for FEC based on RS codes and derive the expressions for QoS on the basis of this model, which comprise four metrics: throughput, packet error rate, delay, and energy efficiency. Then, we apply RS codes with the MIMO channel technology to the cross-layer design. Numerical and simulation results show that the joint design of MIMO and adaptive cooperative FEC based on RS codes can achieve considerable spectral efficiency gain, real-time performance, reliability, and energy utility.