Electroencephalography (EEG) based brain-computer interfaces (BCIs) have attracted increasing attention in the last decade. Previous studies have shown promising potential of using BCIs to provide alternative communication channels between human brains and external devices for people with disabilities. However, for able-bodied people with both hands occupied, the feasibility of using BCIs to provide additional communication channels to augment multitasking capability still needs further exploration. This study attempted to use the steady state visual evoked potential (SSVEP)-based BCI to provide an additional "hand" to cope with more tasks for operators under multitasking when their hands were fully occupied. The performance metrics of multitasking and SSVEP-BCI were analyzed. The results showed that it had little to no impact on the performance of multitasking to use SSVEP-BCI concurrently. On the other hand, the effect of multitasking on the performance of SSVEP-BCI tended to depend on the operators. For some operators, multitasking had very little impact on SSVEP-BCI, while for the others the impact of multitasking tended to be stronger. These findings show the potential of using SSVEP-BCI to perform additional tasks for the operators whose hands are fully occupied by multitasking.