A method for detecting transmission quality is provided. The method includes following steps. First, the second electronic apparatus receives several data packets through a wireless channel. The data packets are sent by the first electronic apparatus. Next, the second electronic apparatus obtains a received signal strength indication and a bit error rate according to the data packets, Then, the second electronic apparatus determines an effective bandwidth according to the received signal strength indication and bit error rate. Afterwards, the second electronic apparatus determines a signal quality index according to the effective bandwidth and a packet delay rate. Therefore, a user of the second electronic apparatus is able to know a connecting status of a wireless media product.