Fr Han Choong-ryul, an ethnic Korean with Chinese citizenship, was found in the north-east of the country, with human rights activists suggesting that North Korea's security services may be involved.
Reports suggest that Chinese police have launched an investigation.
According to The Telegraph, Mr Han was a priest at Changbai Church, in China's Jilin Province.
He was known for helping defectors find new lives after they had crossed the border from North Korea.
The Telegraph has reported that Fr Han's mobile phone was not found with his body, which has the potential to place defectors and those contacting him in danger.
Chinese policy says that refugees who are found are sent back to North Korea, because of this human rights groups have set up series of safe houses that defectors can use until they can to cross a border to another country and then travel further to South Korea.
It is thought it could cost around £6,800 per person to take people out of North Korea, and thousands more is needed to then get them out of China too.
Robert Park, from the Worldwide Coalition to Stop Genocide in North Korea and a former prisoner there, told the paper: "We have had reports of this sort of thing happening before and we have seen a sharp increase in the security on the border with China since Kim Jong-un came to power.
"American and South Korean citizens doing this sort of work in north-east China might be a little safer, but Chinese citizens are in danger because their own government does nothing to protect them."