Abstract：The isolation means and properties of morphology and pacemaker current If in Sino-Atrial Node (SAN) cells of rabbits are investigated. In the present study, the SAN trip containing "the central nodal region" is located by tagging super vena cava with black fine tread as a mark in right atrium of rabbit. The beating pacemaker cell of the SAN is spontaneously isolated by two dIfferent enzymatic digestions. Hyperpolarization-activated pacemaker current is recorded by using whole-cell perforated patch technique in SAN cells. The results show that SAN tissue which include the "central nodal region" is shaped with superior wide and inferior narrow, and with an volume size that is approximately 6.25mm×2.23mm×0.26mm or 6mm×2mm×0.1mm—6mm×2mm×3.3mm. SAN cells are long thin spindle-shaped with faint cross-striations. They are measured with (65.3±7.8)μm in length and (7.2±3.1)μm in width. In normal Tyrode's solution, the typical SAN cells which are 2%—5% in yielded all of them are recovered spontaneous beating with frequency of (187.3±5.6) times/min. According to voltage clamp protocol, If is elicited as the inward ramp current, and becomes larger as soon as is activated more rapidly with the increasingly negative potential. The tail current of If has similar characteristics in same conditions. The current-voltage curve of If and tail is appearing as a typical horizontal "Y" according to their current density and clamp potential. It could be identIfied that the isolated SAN cells have typical morphological properties and activity, therefore could be completely elicited inward ramp If, the fact could contribute to the dIfferent investigations on If in SAN cells in cardiovascular areas.