Wireless LAN IEEE802.11n exploits multiple-input multi-output (MIMO) antenna to gain high throughput. It separates data into some spatial stream so that more robust to multi path fading propagation environment. In this paper, the performance of WLAN IEEE802.11n was evaluated by antenna spacing on both transmitter and receiver. Simulation resented of4x4 MIMO antennas with spacing varied between 2-2. The closer of space can be higher correlation between antenna and higher interference so it gives bad performance but it more efficient in size of hardware. From 2 to 2 we obtain SNR about 5 dB.