"The prayers are to wish peace to the refugees and also to open a channel for the souls, so that they don't go to Hell but to Heaven where they are happy," a monk said.
Temple relief convoys are prevented by authorities from going directly into the disaster zone, said monks who requested anonymity because of the controls on temples in China.
The Chinese government prefers that all aid be channelled through the Chinese Red Cross.
Undeterred, Chengdu's monks accept donations of food and clothing and buy medicine with temple budgets and donated money, in line with the Buddhist tradition of charity and compassion.
Some temples bring donations to the border of the zone for pick-up by local contacts, while others transfer them to the local Red Cross. Some temples have succeeded in getting Red Cross accreditation, and monks have been seen delivering vegetables in the rubble of at least one town.
The earthquake occurred just as Buddhists were celebrating the birthday of Sakyamuni, the historic Buddha, which falls on the eighth day of the fourth month in the Buddhist calendar.
It damaged at least 200 historic temples in Sichuan, killing some people as heavy roofs crashed down.
Famous temples at Dujiangyan, a 2,300-year-old irrigation project, and the Bao'en Temple in Pingwu, one of Sichuan's largest, have collapsed, the China Daily said on Friday.
Other temples at Mount Qingcheng, the birthplace of Daoism, are in danger of falling.