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 (KCU) 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 KCU 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.