Abstract: To accurately test the short circuit of short and light liners in deep and ultra-deep wells, a test method for the circulating pressure curves of variable density slurry was proposed after analyzing conventional test methods for liner short circuits and considering actual construction conditions. The principle and control processes of variable density cyclic tests, operable test programs, and key technical points were studied. The circulating pressure of variable density slurry was highly sensitive to the changes in downhole circulation channels, shown in pressure curves as variations. The comparison between the measured and theoretical pressure curves can reveal the short circuit situation of downhole strings. Field application results prove the test method has the characteristics of strong anti-interference capability, accurate measurement results, and simple operation, which can correctly identify the short circuit of liner strings. The test method for the circulating pressure curves of variable density slurry has overcome the difficulty in testing the short and light liner short circuits in deep and ultra-deep wells, which is worthy of wide application.