Abstract: As a kind of special XML data, probabilistic XML has been also presented as the de facto standard for probability data exchange on the web. And there are a mass of probabilistic relational data. In order to realize the conversion of probabilistic relational data to probabilistic XML data, the representation methods of probability data in the probabilistic relational data and in the probabilistic XML data are firstly analyzed separately. And the probabilistic XML data tree is a classical probabilistic data model with some distribution nodes. The conversion process of probabilistic relational data to probabilistic XML data is composed of two stages what are schema conversion and data conversion. Algorithm PRS2PDTD converts the probabilistic relational schema to the probabilistic DTD, while preserving semantic constraints of the original probabilistic relational schema. And algorithm PRD2PT converts probabilistic relational data to the probabilistic XML data tree. The instance analysis results show that the algorithms are effective methods for conversion of the existent probabilistic relational data to the probabilistic XML data.