Chlorophyll is an indispensable photoreceptor in plant photosynthesis. Its anabolic imbalance can seriously affect individual growth and development. DNA methylation is an essential epigenetic modification that may contribute to environmentally induced phenotypic variations by regulating gene expression. Wheat XN1376B albino line is a natural mutation of XN1376, which performs an albino for about a week under the condition that the average temperature is below 5 °C. However, the regulatory mechanism of albinism is still unclear. In this study, we found that the number of chloroplasts decreases as the phenomenon of bleaching intensifies and the number of fence tissue and sponge tissue slowly dissolves based on the perspective of organizational structure. And then, we identified 6 distinct TaPOR (protochlorophyllide oxidoreductase) genes in the wheat (Triticum aestivum L.) genome, based on a genome-wide scan approach. We found two genes TaPOR1B and TaPOR2D were closely related to the phenomenon of albinism based on the expression analysis in different color leaves (green leaves, red leaves, white leaves and returned green leaves) and analysis of promoters Cis-acting elements. We performed functional characterization of TaPOR2D genes based on the evolutionary relationships among the POR gene families of wheat, rice (Oryza sativa L.), and Arabidopsis. An overexpression analysis of TaPOR2D in Arabidopsis (TaPOR2D-OE) revealed that it affected the accumulation of chlorophyll content in leaves. Compared with wild type (WT), the chlorophyll content of TaPOR2D-OE was significantly higher than that of WT, especially at 2 weeks, the chlorophyll content was 6.46 mg/L higher than WT. The methylation rate of the TaPOR2D promoter in low-temperature albino leaves is as high as 93%, while there is no methylation in green leaves. Correspondingly, three DNA methyltransferase genes (TaMET1, TaDRM, and TaCMT) was up-regulating in white leaves. TaPOR2D was localised to chloroplasts. In summary, we found the natural albino line XN1376B of wheat XN1376. TaPOR2D gene is closely related to the chlorophyll content, and it can cause wheat albinism through its promoter methylation. Our study provides a theoretical basis for in-depth analysis of the regulation of color variation in wheat XN1376B leaves.