The　focus　of　the　study　is　the　estimation　of　the　effects　of　microgravity　on　the　central　nervous　activity　and　its　underlying　influencing　mechanisms.　To　validate　the　microgravity-induced　physiological　and　psychological　effects　on　EEG,　quantitative　EEG　features,　cardiovascular　indicators,　mood　state,　and　cognitive　performances　data　collection　was　achieved　during　a　45　day　period　using　a　-6A　degrees　head-down　bed　rest　(HDBR)　integrated　approach.　The　results　demonstrated　significant　differences　in　EEG　data,　as　an　increased　Theta　wave,　a　decreased　Beta　wave　and　a　reduced　complexity　of　brain,　accompanied　with　an　increased　heart　rate　and　pulse　rate,　decreased　positive　emotion,　and　degraded　emotion　conflict　monitoring　performance.　The　canonical　correlation　analysis　(CCA)　based　cardiovascular　and　cognitive　related　EEG　model　showed　the　cardiovascular　effect　on　EEG　mainly　affected　bilateral　temporal　region　and　the　cognitive　effect　impacted　parietal-occipital　and　frontal　regions.　The　results　obtained　in　the　study　support　the　use　of　an　approach　which　combines　a　multi-factor　influential　mechanism　hypothesis.　The　changes　in　the　EEG　data　may　be　influenced　by　both　cardiovascular　and　cognitive　effects.