Objective To explore the effect of different resistance amount on the reliability of the lumbar muscles' coordination test.Methods 30 young male adults participated the lumbar muscles' coordination test twice within 1 week by the same tester. In each test, the subjects took 5 kg, 10 kg and 15 kg of resistance randomly. The index included mean of concentric motion, deviation of concentric motion, mean of eccentric motion and deviation of eccentric motion. Intra-class correlation coefficient (ICC) for these 4 test results were applied to evaluate the reliability of those tests. Results The ICCs of the 4 test results were 0.303, 0.500, 0.358 and 0.360 respectively in the 5 kg of resistance group, 0.449, 0.382, 0.365 and 0.272 respectively in the 10 kg of resistance group, and 0.453, 0.442, 0.614 and 0.411 respectively in the 15 kg of resistance group. Conclusion The test-retest reliability can be satisfied in the lumbar muscles' coordination test with 15 kg of resistance.