Objective To explore ultrasound visualized intrahepatic localization marker as the reference object of the tumor location and safety margin in radiofrequency ablation（RFA）, aiming at precisely guiding ablation region to prevent from tumor local recurrence caused by inaccurate electrode needle placements. Methods A total of 24 medical materials were selected in this study, including 1 gas, 18 liquids, and 5 solids. In bovine liver experiment in vitro，ultrasound-guided puncture was performed and localization markers were inserted or injected into the bovine liver. Then the visibility and persistence in situ of the markers were evaluated using ultrasound images. Further，local ablation was performed at a distance of 1cm, 0.5cm and 0cm between the radiofrequency electrode needle and the markers，monitoring the effect of the thermal field on the markers. In animal models, visualized localization markers were put into the liver of living beagle dogs under the guidance of ultrasound to observe the effect of liver blood perfusion, breath, heartbeat as well as the heat-sink effect in ablation on the markers. The animals were observed for 7 days after RFA recording complications and reexamined by ultrasound on the 7th day. Then the ablation sites were dissected to observe the markers location and the damage of the liver tissue. Results In vitro experiments showed that air, sodium bicarbonate, gelatin sponge, PGA absorbable suture, 5 mm metal, SonoVue-F127，calcium alginate, ultrasonic couplant, lauromacrol had both good ultrasound visibility and persistence. After radiofrequency ablation, at 0.5 cm and 1.0 cm away from the ablation needle, various markers can be clearly displayed in ultrasound images without being affected by ablation thermal field. Close to the ablation needle, only metal and calcium alginate could still be seen by comet tail sign or backward attenuation. In animal experiments, air, PGA absorbable suture, 5mm metal and ultrasonic couplant were implanted into the dog liver and showed good ultrasound visibility and persistence. Immediately after radiofrequency ablation, all of the above four material markers were visible by ultrasound. 7 days later, reexamination showed that the metal was still clearly displayed by ultrasound, and gross specimens showed that only the implanted metal was visible macroscopically. The breathing and heartbeat of the dogs were stable during the puncture implantation, and no complications such as bleeding and infection occurred within 7 days. No liver tissue damage was noted in histopathological examination. Conclusion The gas marker with clear and durable visibility and simple availability，while controlling injection speed and dosage，is expectably served as a location marker to guide precise ablation needle placements. As to the couplant and the SonoVue-F127 showing obvious difference with hepatic background echo, intrahepatic marker may become a new clinical application. The metal marker could be stably retained in situ after RFA making it an ideal marker for long-term tumor localization.