The invention provides a building-out circuit and a testing method for testing the 
negative bias temperature instability (NBTI). The building-out circuit is respectively connected with a source-measurement unit and a PMOS (P-channel 
Metal Oxide Semiconductor) to be measured; the building-out circuit comprises an NMOS (N-channel 
metal oxide semiconductor); a base 
electrode of the NMOS is electrically connected with a source 
electrode of the NMOS by a 
resistor R0; a drain 
electrode fo the NMOS is electrically connected with a grid electrode of the PMOS to be measured by a 
resistor R1; a grid electrode fo the NMOS is electrically connected with the grid electrode of the PMOS to be measured by a 
resistor R2; the potential of the base electrode of the NMOS is set into a value of less than 0V; and the 
voltage input end of the source-measurement unit is connected with the grid electrode of the NMOS. When an input 
voltage of the source-measurement unit is changed into 0V, due to the 
voltage division of the resistor R2, the voltage of the grid electrode of the PMOS to be measured is less than 0V, i.e. when the NBTI 
recovery effect occurs after the stress voltage is switched off, a 
partial pressure of the R2 is still applied to the grid electrode of the PMOS to be measured to inhibit the NBTI 
recovery effect in the PMOS, so that the measurement result is more accurate.