Many studies have provided significant insights into polyploid breeding in recent years, but limited research has been carried out on trees. The genomic information needed to understand the growth and response to abiotic stress in polyploidy trees is largely unknown, but has become critical due to the threats to our forests imposed by climate change. Populus alba 'Berolinensis', also known "Yinzhong poplar", is a triploid poplar from the northeast of China. This hybrid triploid poplar is widely used as a landscape ornamental and in urban forestry for its adaptation to adverse environments and fast growth than its parental diploid. It is an artificially synthesized male allotriploid hybrid, with three haploid genomes of P. alba 'Berolinensis' originated from different poplar species, so it is attractive for studying polyploidy genomic mechanisms in heterosis. In this study, we focused on the allelic genomic interactions in P. alba 'Berolinensis', and generated a high-quality chromosome-level genome assembly consisting of 19 allelic chromosomes. Its three haploid chromosome sets are polymorphic with an average of 25.73 nucleotide polymorphism sites per kilobase. We found that some stress related genes such as RD22 and LEA7 exhibited sequence differences between different haploid genomes. The genome assembly has been deposited into our polyploid genome online analysis website TreeGenomes (https://www.treegenomes.com). These polyploid genomic related resources will provide a critical foundation for the molecular breeding of P. alba 'Berolinensis' and help us uncover the allopolyploidization effects of heterosis and abiotic stress resistance and traits of polyploidy species deeper in the future.