Hydro-mechanical behaviors of a saturated clay with various strain-rate and different stress histories are investigated through a series of consolidated-undrained and K consolidated undrained (K CU) tests which were conducted on reconstituted specimens. The samples were taken from an excavation site in Macau and reconstituted in the laboratory to provide homogenous specimens. A total of four CU tests and four K CU tests were undertaken on 38 mm diameter samples. The samples were saturated first by use back pressure saturation method (back pressure 200 kPa), after saturation, they were loaded to a confining stress 400 kPa and then unload to 50 kPa, 100 kPa, 200 kPa, 400 kPa (OCR = 8, 4, 2, 1) and finally were sheared at constant shear rate (0.1%/h, 1%/h, 10%/h) to failure. In this research the responses of marine clay under various strain rates under different OCRs on the strain-rate effects will be discussed, parameters for accounting the strain-rate effects on undrained shear strength will be proposed.