In order to explore the rules of releasing monospores of Pyropia, we used the wild-type strain(PC-WT) and its mutant strain(PC-Y1) in Pyropia chauhanii as materials, to study the rules of releasing monospores on the blades discs from different ages and different parts. The results showed that the discs from different ages or different parts of PC-WT blades, the time and number of releasing monospores had a certain difference during two weeks of culture. Discs from the apical, middle and basal parts of the 40-day-old blades did not display sexual cells, the daily number of releasing monospores showed a trend of increasing first and then decreased, and the order of total number after culture of 12 days was middle > apical > basal. The discs from the apical and middle parts of the 45-day-old blades had sexual cells already, and the time to release monospores became earlier as compared with the 40-day-old blades, but the total number of monospores declined, the collapse speed of discs was faster, and the order of total monospore number was middle > apical > basal. The discs from the apical and middle parts of the 50-day-old blades collapsed completely on the 6^th days and 10^th days of culture, respectively, and it was found that the discs almost matured, the total number of monospores was less, while the discs from basal part did not mature, and the total number of monospores was the greatest. The discs from the apical, middle and basal parts of PC-Y1 blades grew well with edge integrity, and did not release monospores. The discs from the 40-day-old blades did not present sexual cells, and its vegetative cells were bright-red and tight. The discs from 45-day-old and 50-day-old blades presented sexual cells. These results indicated that PC-WT is a strain which can release monospore, the monospore releasing time order was apical > middle > basal; With the increase of the blades age, the time of releasing monospores became earlier, but the total number of monospores decreased; The PC-Y1 is a strain which released no monospore at different ages or from different parts of the blades, indicating that its genes linked to the formation and release of monospore had probably mutated.