The Palestine Solidarity Campaign's anti-Israel rhetoric is "infused with antisemitism" and its members engage in "racist conspiracy theories," according to the Board of Deputies.
Attacking the group and its Scottish counterpart, the Board said the PSC's recent actions reinforced the view that it had become an "impediment" to peace.
PSC director Sarah Colborne said the claims were "smears and false allegations".
Board president Vivian Wineman said a number of campaigns in the past six months highlighted how the PSC had been "totally discredited".
In July, the chair of Waltham Forest PSC, Ellie Merton, claimed Anders Breivik's massacre in Norway, in which more than 70 people were killed, was "an Israel government-sponsored operation". The PSC said her views did not represent those of the campaign, but did not remove her from her role.
Scottish PSC members last week led demonstrations in support of the student found guilty of racially abusing a Jewish postgraduate, lambasted the sheriff who heard the case and pledged to protest at the guilty student's sentencing.
Mr Wineman said: "We are alarmed by the way in which anti-Israel rhetoric has now become infused with antisemitism and members of organisations which claim to be combating racism are in fact now engaging in racist conspiracy theories and condoning racist acts.".
Mark Gardner, CST communications director, said: "In their extreme hatred of Israel and its supporters, PSC and the wider anti-Israel movement risk echoing the old ugly themes about evil Jewish power and conspiracy."
On Wednesday PSC members demonstrated outside a London art gallery hosting a show by gay Israeli artists.
Ms Colborne attacked the exhibition as an attempt by Israel to "co-opt the LGBT community into its 'pinkwashing' campaign, which aims to rebrand Israel as a haven for queers while drawing attention away from its numerous crimes against the Palestinian people".
The PSC was due to picket yesterday's performance by the Israel Philharmonic Orchestra at the Royal Albert Hall.
Responding to the criticism, Ms Colborne insisted: "Those few organisations and individuals who still uncritically support Israel's policies are finding it so difficult to justify Israel's war crimes and illegal occupation that they are resorting to attacking those defending human rights."