The effects of ionomycin, electrical pulses, dithiothreitol (DTT), 6-DMAP and thimersal,used either alone or in combinations, on the activation rate, pronuclear type and cleavage of porcine oocyte were studied in this paper. The results are as follows: (1) The activation rates of oocytes treated with ionomycin (88.9%) or pulsed (80.0%) alone did not differ significantly from each other and from those in oocytes treated in combination with 6-DMAP (84.3 and 79.1%, respectively). While 6-DMAP improved electrical activation (increased the proportion of oocyteswith 1 PN), it had no effect on oocyte activation by ionomycin;(2) Post-treatment with DTT significantly enhanced the thimersal activation of porcine oocytes with activation rates increased from 4.6 to 82.6%; (3) When pulsed, the activation rates of oocytes with crimped (85.4%)or fragmented first polar bodies (86. 2%) were significantly higher than those of oocytes with intact polar bodies (58.8%); the ratio of 1 PN activated oocytes (78.8%) was significantly higher, but that of 2 PN oocytes (18.2%) was significantly lower in oocytes with intact polar bodies; (4) The cleavage rate of oocytes activated by electrical stimulus (52.4 %) was significantly higher than that in oocytes activated by ionomycin (23.0%) when combined with 6-DMAP, but it was not significantly different from that in oocytes activated by electrical stimulus alone (46.1%).