Disclosed are a blood tester for measurement of temperature of a sample placed in a blood-testing disc using a thermochromic pigment, and a control method thereof. The disclosed blood-testing disc, the blood tester having the blood-testing disc loaded therein, and the control method of the same, are used to measure a light absorbance of the thermochromic pigment in order to determine a temperature of a sample when a biological material such as blood, blood serum, blood plasma, or sputum, is subjected to analysis, so that the test may be executed at a constant temperature. Accordingly, more reproducible and accurate results are obtainable, and temperature measurement of a sample may be simply and effectively attained by an optical analyzer built in the blood tester, without an alternative instrument or sensor for measurement thereof.