WE CLAIM:
1. A filtering material, wherein
the filtering material comprises at least four layers of structures,
the filtering material comprises a first polyphenylene sulfide melt-blown nonwoven cloth filtering layer, a second heat-resistant fiber mesh filtering layer, a third fabric reinforcing layer and a fourth heat-resistant fiber mesh non-filtration layer, and
an average diameter of the fibers constituting the first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is 0.5 to 10.0 μm.
2. The filtering material according to Claim 1, wherein the proportion of the polyphenylene sulfide fibers having a diameter of 0.5 to 10.0 μm in said first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is 0 to 2.0% by weight in the other three layers.
3. The filtering material according to Claim 1, wherein the average diameter of the fibers constituting said first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is 1.0 to 5.0 μm.

4. The filtering material according to Claim 1, wherein the proportion of the fibers, having a diameter of 0.1 to 6.0 um, constituting the first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is 20 to 100%.
5. The filtering material according to Claim 1, wherein the average pore diameter of said filtering layer is 2.0 to 15.0 um.
6. The filtering material according to Claim 1 or 5, wherein the pore diameter in the range of 1.0 to 20.0 um in said filtering material accounts for more than 90%.
7. The filtering material according to Claim 1, wherein the total basis weight of said second heat-resistant fiber mesh filtering layer, third fabric reinforcing layer and fourth heat-resistant fiber mesh non-filtration layer is 300 to 800 g/m2, and the density of the filtering material is 0.2 to 0.5 g/cm3.
8. The filtering material according to Claim 1, wherein the cross section of the fibers constituting the first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is a circular cross section or an irregular cross section.

9. The filtering material according to Claim 1, wherein the basis weight of said first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is 5 to 100 g/m2.
10. The filtering material according to Claim 1, wherein said first polyphenylene sulfide melt-blown nonwoven cloth layer further comprises a heat-resistant fiber mesh layer having a basis weight below 200 g/m2.
11. The filtering material according to Claim 1, wherein the diameter CV% of the fibers constituting said first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is below 100%.
12. The filtering material according to Claim 1, wherein the thickness at any one point of said first polyphenylene sulfide melt-blown nonwoven cloth layer is between 20 and 600 μm.
13. The filtering material according to Claim 1, wherein the thickness CV% of said first polyphenylene sulfide melt-blown nonwoven cloth filtering layer is less than 50%.