Abstract: A novel hybrid single cavity (HSC) linac, formed by combining a radio frequency quadrupole (RFQ) structure and a drift tube (DT) structure into one interdigital-H (IH) cavity, was fabricated, assembled and tested as a proof of principle type injector for cancer therapy synchrotron. The HSC linac is a power-efficient cavity. The low power test and the high power acceleration test were carried out. The low power test results are in good agreement with the calculation results. The high power test results show that the HSC linac can meet the high power test in the next step.