Abstract: In order to study the effects of surgically implanted dummy ultrasonic transmitters on grass carp Ctenopharyngodon idella, two experiments were conducted from October 2010 to December 2010 and November 2010 to October 2011. The results showed that surgical implantation of dummy ultrasonic transmitters had a significant negative influence on the growth of grass carp within 30 days following the surgery. However, the negative influence after 30 days faded away. One and two fish died during the 60-day and 360-day experiments, equivalent to the mortalities of 4.2% and 6.7%, respectively. All fish incisions were completely healed in 30 days after surgery, and all sutures were lost in 360 days after surgery. Two and one fish expelled the transmitters through the unclosed wound during the 60 days and 360 days, and the discharges were 8.7% and 3.3%, respectively. All the remaining transmitters were encapsulated in fibrous capsules and adhered to body wall, intestinal tract or viscera multiply. The result suggested that surgical implantation of ultrasonic transmitters could be applied to the ultrasonic telemetry research on grass carp. Nevertheless, the grass carp should be given for at least 30 days with the purpose of incision healing and growth recovery from the surgical procedure.