When did China communicate with the Malay Peninsula? '

During the Spring and Autumn Period and the Warring States Period, merchants from South Asia and Malay Peninsula trafficked goods in Lingnan and sold them to the Central Plains through middlemen.

The real contact was in the period of Emperor Wu of Han Dynasty.

During BC 1 1 1-87, Emperor Wudi sent translators attached to Huangmen (the emperor's attendants) to recruit "applicants" to form an official fleet, which consisted of Nanzhangsai (Western Han Dynasty, now Da Nang, Vietnam), Xuwen and Hepu (now Hepu County, Guangxi). The fleet sailed along Indochina Peninsula, passing through Vietnam, Thailand, Malaysia, Myanmar and other places today, sailing to Huang Zhiguo (now Kangchipulan, India), and finally arriving in that country (now Sri Lanka) and returning.