THE wife of the mastermind of a scheme to bring Thai women to Hong Kong for prostitution through marriages of convenience has been jailed for 12 months. Cheung Amornrat, 23, pleaded guilty to aiding and abetting the trafficking of a woman into the territory from Thailand for prostitution. Her co-accused Tong Hoi-nam, 35, also pleaded guilty to two similar charges and two counts of living on the earnings of another person's prostitution. He was jailed at the District Court yesterday for a total of 18 months. Deputy Judge Meredith said both defendants aided Cheung Amornrat's husband, Cheung Wan-luen, who masterminded the scheme and is still at large. Cheung's counsel, Liza Yip, said her client first met Cheung Wan-luen at her workplace in Bangkok, where he was a tour guide for mainland tourists. Shortly after her arrival in Hong Kong, her father wrote her asking for money to finance her brother's education. But her husband refused to pay. Cheung was convicted for soliciting for immoral purposes in November 1991. Her husband found out, and agreed to pay her more each month. Miss Yip said Cheung was kept pretty much in the dark about the scheme to bring Thai women into Hong Kong. She had only helped her husband by running errands. The court heard Cheung went to the Immigration Department as instructed by her husband in January 1992 with local man Suen Yin-kwong and his ''wife'' Jamlong Jankao, to get Jamlong a permit to stay. Suen, who agreed to be recruited as a ''husband'' in return for $23,000, had married Jamlong in Thailand in August 1991. Counsel for Tong, Robert Buchanan, said his client was married with a three-year-old daughter in China. Tong, now a noodle shop worker, had committed the offence when he was unemployed, he said. Prosecuting counsel Newman Wong said Tong aided and abetted Cheung Wan-luen by introducing two local men to him, who were willing to take part in the marriages. As a result, Suen and Kam Wing-ming went through marriages of convenience in Thailand with Jamlong and Suksri Katib, both 22. Tong admitted that between July 1992 and February 7 this year, two other Thai women - Phaboijawong Nuay and Chida Napaora - worked as prostitutes under him. Tong got $40 for each client.