A biochemical ball includes a first half, a second half, and a plurality of sponge filters. The first half has a plurality of first ribs, a first rim, and a first partition. The first partition divides the first half into a plurality of equal first accommodating spaces. The first rim of the first half is provided with a first fastener and a connecting joint. The second half has a plurality of second ribs, a second rim, and a second partition. The second partition divides the second half into a plurality of equal second accommodating spaces. The second rim of the second half is provided with a second fastener configured to correspondingly engage with the first fastener. The sponge filters are so received in the first and second accommodating spaces that the sponge filters are separated without contacting each other, thereby enhancing filtering efficiency.
