* Four Chinese leasing firms place orders for C919
* C919 orders rise to 730 planes from 27 customers
* AgBank Leasing says placed down payment for orders
* Chinese airlines will need 8,575 new planes over 20 years -COMAC (Update with COMAC's 20-year market forecast)
BEIJING, Sept 19 (Reuters) - China's Commercial Aircraft Corp of China Ltd (COMAC) on Tuesday signed 130 new orders for its C919 passenger jet with four Chinese leasing firms, after the plane took its maiden flight in May this year.
COMAC is leading China's efforts to become a key player in the global civil aerospace market, threatening the dominance of U.S. and European rivals Boeing Co and Airbus.
The deals take total orders for the C919 single-aisle aircraft to 730 planes from 27 customers.
China Nuclear E&C Group placed an order for 40 jets, while Huabao Leasing and AVIC International Leasing each signed up for 30 of the aircraft, according to a statement from COMAC.
Agricultural Bank of China (ABC) Financial Leasing Co Ltd became the first customer to make a second order for the C919 jet, making 20 firm orders and an intention to buy 10 more.
ABC Financial Leasing has made down payments of about 500,000 yuan ($75,882.90) for each firm order, the firm's chairman Wang Yigang told reporters. COMAC did not ask for down payments before the jet's maiden flight, industry sources say.
"Our confidence in the C919 firmed after the plane's successful maiden flight," Wang said, declining to give more details on pricing. The firm signed up for 45 C919 jets in 2012.
Wang added the firm was in talks with both foreign and domestic airlines to lease out the planes, with a focus on carriers in regions such as Central Asia and Africa that were involved in Beijing's Belt and Road initiative.
COMAC, though still some way away from delivering the first C919 for commercial use, is pushing towards getting it certified in Europe and the United States to open up markets beyond those that accept China's certification standards.
Separately, COMAC predicted Chinese airlines will need 8,575 new planes worth $1.21 trillion over the next 20 years as strong travel growth continues.
This was higher than a recent forecast by Boeing, which said the country's airlines would spend $1.1 trillion on more than 7,000 planes for the period to 2036. ($1 = 6.5891 Chinese yuan renminbi) (Reporting by Brenda Goh, writing by Adam Jourdan; Editing by Himani Sarkar)