正好用到，作为纪录，代码丢完就走

//验证身份证号码
+(BOOL)checkIdentityCardNo:(NSString*)cardNo
{
    if (cardNo.length != 18) {
        return  NO;
    }
    NSArray* codeArray = [NSArray arrayWithObjects:@"7",@"9",@"10",@"5",@"8",@"4",@"2",@"1",@"6",@"3",@"7",@"9",@"10",@"5",@"8",@"4",@"2", nil];
    NSDictionary* checkCodeDic = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:@"1",@"0",@"X",@"9",@"8",@"7",@"6",@"5",@"4",@"3",@"2", nil]  forKeys:[NSArray arrayWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"10", nil]];
    
    NSScanner* scan = [NSScanner scannerWithString:[cardNo substringToIndex:17]];
    
    int val;
    BOOL isNum = [scan scanInt:&val] && [scan isAtEnd];
    if (!isNum) {
        return NO;
    }
    int sumValue = 0;
    
    for (int i =0; i<17; i++) {
        sumValue+=[[cardNo substringWithRange:NSMakeRange(i , 1) ] intValue]* [[codeArray objectAtIndex:i] intValue];
    }
    
    NSString* strlast = [checkCodeDic objectForKey:[NSString stringWithFormat:@"%d",sumValue%11]];
    
    if ([strlast isEqualToString: [[cardNo substringWithRange:NSMakeRange(17, 1)]uppercaseString]]) {
        return YES;
    }
    return  NO;
}

实际使用场景

- (void)textFieldDidEndEditing:(UITextField *)textField{
    if (textField == _tfId) {
            if (![MyTool checkIdentityCardNo:textField.text]) {
                [self showMessage:@"请输入合法的身份证号"];
                _tfId.text = @"";
            }
    }
}