Wireless network device and automatic parameter setting method thereof

A wireless network device and an automatic parameter setting method thereof are provided. The device includes a wireless communication module and an operation module. The wireless communication module is used for transmitting a test signal to a wireless device according to a wireless communication protocol, and receiving an ACK frame transmitted by the wireless device. The operation module is electrically connected to the wireless communication module, and is used for calculating one half of a sum of a minimum transmission time and a maximum transmission time, setting the half of the sum as an ACK timeout interval of the wireless communication module, analyzing whether the ACK frame is obtained within the ACK timeout interval so as to determine whether to use the ACK timeout interval as the maximum transmission time or the minimum transmission time, and recalculating the ACK timeout interval.