Single-cell genome and transcriptome sequencing investigates how genotype influences the phenotype of single cells, so as to comprehensively interpret biological inheritance and explain functional heterogeneity at the single-cell level. Current sample preparation technologies for simultaneous DNA and RNA sequencing of the same cell are cumbersome, expensive, and suffer from cross-contamination and limited sensitivity. Herein we describe DMF-DR-seq, a nanoliter-scale single-cell multi-omics sample preparation platform based on digital microfluidics. DMF-DR-seq integrates the major steps of single-cell isolation, DNA/RNA separation, and nucleic acid amplification in situ. The results confirm the enhanced ability of DMF-DR-seq relative to current state-of-the-art technology, with lower amplification bias, higher genome-wide coverage in DNA sequencing and better gene detection ability in RNA sequencing results. By using DMF-DR-seq, we identified the genome variation-induced abnormal transcriptome expression of single circulating tumor cells (CTCs) and cancer cells from multiple myeloma patients. The results identified potentially essential genes, known as transporters associated with antigen presentation (TAP1 and TAP2), that participate in the pathologic progress. The unique flexibility, sensitivity, and accuracy of DMF-DR-seq suggest its potential utility in deeper multi-omics analysis for inheritance mechanism study in single-cell biology.