@@ Circadian rhythms can be found at levels of physiologicai function,biochemical metabolism and behavior change for 24 hs which is the regular cycle in human and animals．Signal output of the rhythm in vivo， generated by endogenous biological clocks，not only regulate various activities spontaneously but also receive resetting bv the entrainment with extemal environmental factors named zeitgeber,in order to make body activities be in accordance with environmental changes．The molecular regulatory mechanisms of clock oscillation consist of clock signal input,several clock genes，clock-associated genes，clock-controlled genes and their protein．Through the interconnection of intracellular transcription—translation-posttranslation event，to organize a fundamental molecular framework named autoregulatory feedback loop of the clock oscillator for accurate clock signal output．Of core clock genes．The Clock and Bmal l genes whose product I．E．Heterodimer has been together regarded as a cruelal positive transcription regulator in the loop，have been evidenced the 24．Hour rhythmic expressions not only in central clock tissues such as the suprachiasmatic nucleus(SEN)and the pineal gland(PG)，but also in various peripheral clock tissues including blood cells．The research of core clock genes Clock and Bmal l circadian expressive profile has been reported at Mrna levels in human peripheral blood lymphocytes．However,study on tireadian rhythmic expressions and photoresponses of CLOCK and BMAL1 proteins in human peripheral blood lymphocytes is not clear so far,which is an aim of present study．