方法一：

//cell分割线与屏幕等宽，两个方法同时添加iOS 10有效
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
        [cell setSeparatorInset:UIEdgeInsetsZero];
    }
    if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
        [cell setLayoutMargins:UIEdgeInsetsZero];
    }
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
    if ([tableView respondsToSelector:@selector(setSeparatorInset:)]) {
        
        [tableView setSeparatorInset:UIEdgeInsetsZero];
        
    }
    
    if ([tableView respondsToSelector:@selector(setLayoutMargins:)]) {
        
        [tableView setLayoutMargins:UIEdgeInsetsZero];
        
    }
}

方法二：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    
    //设置全局cell分割线与屏幕等宽
    [[UITableView appearance] setSeparatorStyle:UITableViewCellSeparatorStyleSingleLine];
    [[UITableView appearance] setSeparatorInset:UIEdgeInsetsZero];
    [[UITableViewCell appearance] setSeparatorInset:UIEdgeInsetsZero];
    
    if ([UITableView instancesRespondToSelector:@selector(setLayoutMargins:)]) {
        [[UITableView appearance] setLayoutMargins:UIEdgeInsetsZero];
        [[UITableViewCell appearance] setLayoutMargins:UIEdgeInsetsZero];
        [[UITableViewCell appearance] setPreservesSuperviewLayoutMargins:NO];
    }
    
    return YES;
}