According to the features of analog record for magnetic diurnal variation, the authors implemented the function of printing the magnetic diurnal variation by using D/A conversion chip. With D/A conversion chip as the main part, the case and connector were designed. The software is compiled by Visual Basic, and its function and operation were described. The test of measured data and the comparison with the curve from actual measurement indicate that there exists a high level of consistency between them, and it is feasible to copy analog record of magnetic diurnal variation by using the software and hardware from this paper. The technique is conducive to saving and sharing the analog record of magnetic diurnal variation and promoting the unattended work of magnetic diurnal variation measurement.