Two-dimensional echocardiography was used to guide and locate the balloon of Swan-Ganz catheter during catheterization in 43 patients. The echoes of balloon appeared as a series of strong light spots, with a rate of detection of 100%. Under monitoring of two-dimensional echocardiography, the site of balloon and its moving route could be determined. The coincidence of echographic findings and X-ray findings showed that it can be used instead of X-ray monitoring to lessen irradiation during catheterization. The depth of catheter inserted was measured. The differential points between the echoes of balloon and tubing, the terminology of the balloon site in echocardiography and fluoroscopy, its clinical value and limitation are discussed.