Electrochemotherapy (ECT) is a novel cancer treatment in which electric pulses (EPs) inducing cell membrane pored (electroporation) are used as a means of delivering antitumor drugs to the cytoplasm of cancer cells. The minimal thresholds of electric field strength of in vitro tumor cell line and tumor tissue are 450-650 V/cm and 400-600 V/cm, respectively. The typical electrical requirement is 600-1300 V/cm, pulse width of 100 micros, 8 pulses, 1 Hz. More than 10 kinds of antitumor drugs have been applied to ECT, in which the most efficacious drug is Bleomycin, and then Cisplatin. Some exciting inhibitory effects on cells in vitro and on solid tumors in clinical trials have been noticed. The factors influencing ECT effects include the electric parameters, diameter of electrode, distribution of electric field lines, size of tumor, model of drugs injection and kinds of drugs. Some questions of ECT are still open, such as the dosages and kinds of drugs for clinical trials, model of drug injection, influence on normal tissues, therapeutic mechanism.