When we use mouse for a long time..our hand will feel tired n uncomfortable..what wrong with it..tq?

Repetitive injury: You may be describing a repetitive injury such as carpal tunnel syndrome. If uncomfortable sensation of tiredness goes away soon after you stop using mouse, check out your ergonomics, eg how you're sitting, how mouse is placed/used relative to your position. Also change your method of use frequently. If that's not enough, go see your family doc who might prescribe a splint or refer you to hand doc.