The invention discloses porous high borosilicate and a preparation method thereof. The preparation method of the porous high borosilicate comprises the following steps: S1, providing high borosilicate powder and Fe3O4 powder, and mixing high borosilicate powder with Fe3O4 powder, wherein the mass percent of the Fe3O4 powder in the formed mixed powder is 1-6%; S2, grinding the mixed powder formed in S1; S3, preparing a powder base from the mixed powder grinded in S2; S4, sintering the powder base in S3, and discharging after cooling. Porous high borosilicate glass can be obtained by the preparation method disclosed by the invention, the preparation method is simple in steps, low in cost, free of residues and free of pollution, control on environmental protection, cost and the like can be better carried out.