Beijing has for decades been close to neighbouring Myanmar's authoritarian military leaders, who voters overwhelmingly rejected in historic polls.
Suu Kyi's party secured a landslide election victory today, propelling the country's pro-democracy movement to power after a 25-year struggle.
US President Barack Obama was quick to offer congratulations to Suu Kyi, but a Chinese foreign ministry spokesman was circumspect.
"China will continue to extend its assistance and continue with its friendship and all-around mutually beneficial cooperation" with Myanmar, Hong Lei said following the victory.
"We sincerely wish that Myanmar can have political stability and that it can achieve national development," he added at a regular briefing.
China was a key backer of the country's brutal military junta - which kept Suu Kyi under house arrest for more than 15 years - while it was under Western sanctions.
Myanmar is already seen as drifting away from its former dependence on Beijing and towards the US since launching moves towards civilian rule in 2011 which saw sanctions lifted.
China has taken a pragmatic approach to Suu Kyi since it became clear that the party she leads would likely take power.
China frequently congratulates other countries on their successful elections, even ones whose democratic credentials are questioned in the West.
Right on China's doorstep and a key source of natural resources, Myanmar is a sensitive case for the one-party state, which itself has long resisted calls to embrace democratic elections.
