Thermotherapy has been a promising method to treat tumor. In recent years, electromagnetic thermotherapy (EMT) has been extensively investigated and holds the potential for a variety of medical applications including for cancer treatment when combined with minimally invasive surgery approach. In this study, an alternating electromagnetic frequency was provided by an EMT system to heat up stainless steel needle arrays which were inserted into the target tumor to a high temperature, therefore leading to local ablation of the tumor. A new two-section needle-array apparatus was further demonstrated to encompass the tumor to prevent the tumor cells to spread after the treatment process. By using the needle-array insertion apparatus, there is no limitation of the treatment area; this method could, therefore, be applied for tumors that are larger than 6 cm. It was first successfully demonstrated in the in vitro experiments on porcine livers. Then an in vivo experiment was directly conducted on pigs. The two-section needle array incorporated with the needle-array apparatus and EMT was demonstrated to be promising for no-touch isolation treatment of cancerous tumors.