The authors described the procedures for the establishment of clone 515 of the cell strain of osteochondrosarcoma by capillary method.A single cell was sucked into a capillary tube by a microsyringe under the control of a micromanipulator.A segment of the capillary tube with the cell was then planted into the plasma clot in a Carrel flask. After the addition of conditioned medium,the flask was incubated at 37℃.Daily ob- servations were made.The propagation of the single cell,the migration of its progenies out of the capillary tube and the change in form and size of the cells were recorded. 63 days after the isolation,the progenies covered the whole bottom of the flask.First subculture was then made and the clone was established therefrom.