Abstract: To explore the relationship between freshness and cooking quality of tuna steaks, the variation of moisture loss rate, weight loss rate, colour and textual properties of yellowfin tuna steaks of different freshness before and after cooking were studied.The results indicated that through cooking, moisture content of tuna steak decreased significantly ( p < 0.05) , while hardness, springiness, cohesiveness and chewiness increased significantly ( p < 0.05) .With freshness decreasing, moisture content, hardness, cohesiveness and chewiness of tuna steak after cooking decreased significantly ( p < 0.05) , contrary to moisture loss rate and weight loss rate ( p < 0.05) , but springiness had no significant variation ( p > 0.05) . ΔE* value ( Total Colour Difference Value) of tuna steak after cooking increased slowly with decreasing of freshness.However, the colour difference after cooking among tuna steaks of different freshness which belonged to first level of freshness ( K value < 20%) could not be distinguished by naked eye.Due to the effect of freshness on cooking quality in some degree, raw material's freshness should be considered as an important factor in the control of cooking quality of tuna product.