Two- and three-gluon glueballs of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>C</mml:mi><mml:mo>=</mml:mo><mml:mo>+</mml:mo></mml:mrow></mml:math>

We study two- and three-gluon glueballs of $C=+$ using the method QCD sum rules. systematically construct their interpolating currents, find that all spin-1 currents vanish. This suggests ``ground-state'' do not exist within relativistic framework. calculate masses two-gluon with ${J}^{PC}={0}^{\ifmmode\pm\else\textpm\fi{}+}/{2}^{\ifmmode\pm\else\textpm\fi{}+}$ ${J}^{PC}={0}^{\ifmmode\pm\else\textpm\fi{}+}/{2}^{\ifmmode\pm\else\textpm\fi{}+}$. propose searching for ${J}^{PC}={0}^{\ensuremath{-}+}/{2}^{\ensuremath{-}\ifmmode\pm\else\textpm\fi{}}/{3}^{\ifmmode\pm\else\textpm\fi{}\ensuremath{-}}$ in three-meson decay channels future BESIII, GlueX, LHC, PANDA experiments.